Customary International Law

Introduction

According to Article 38 of its Statute, the International Court of Justice 'whose function is to decide in accordance with international law such disputes as are submitted to it,' has to apply, inter alia, 'international custom.' This source of public international law is described, in the same Article, as 'evidence of a general practice accepted as law.' This description of international custom, even though it has been criticized for its exact formulation, at least makes clear that international custom generally refers to a description of State practice, but only such practice as is accepted by the States themselves as legally required. Once a certain practice is understood to be customary law, States are obliged to act as the rule of customary international law prescribes. International customary law is probably the most disputed and discussed source of international law. For example, it is not clear when a particular State practice becomes a legally binding State practice. It is also unclear how one can identify a rule of international custom, or how one can prove its existence.

The International Law Commission appointed Sir Micheal Wood as Special Rapporteur concerning the issue of Customary International Law. One can read about his reports and his recommendations at this website.

This Research Guide is intended as a starting point for research on Customary International Law. It provides the basic legal materials available in the Peace Palace Library, both in print and electronic format. Handbooks, leading articles, bibliographies, periodicals, serial publications and documents of interest are presented in the Selective Bibliography section. Links to the PPL Catalogue are inserted. The Library’s systematic classification index subject 'Sources' and subject heading (keyword) Customary International Law are instrumental for searching through the Catalogue. Special attention is given to our subscriptions on databases, e-journals, e-books and other electronic resources. Finally, this Research Guide features links to relevant websites and other online resources of particular interest.

New titles

Seems like there are no recent acquisitions right now''.

Librarian's choice

Green, J.A., The Persistent Objector Rule in International Law, Oxford, United Kingdom, Oxford University Press, 2016.

The persistent objector rule is said to provide states with an 'escape hatch' from the otherwise universal binding force of customary international law. It provides that if a state persistently objects to a newly emerging norm of customary international law during the formation of that norm, then the objecting state is exempt from the norm once it crystallizes into law. The conceptual role of the rule may be interpreted as straightforward: to preserve the fundamentalist positivist notion that any norm of international law can only bind a state that has consented to be bound by it. In reality, however, numerous unanswered questions exist about the way that it works in practice. Through focused analysis of state practice, this monograph provides a detailed understanding of how the rule emerged and operates, how it should be conceptualized, and what its implications are for the binding nature of customary international law. It argues that the persistent objector rule ultimately has an important role to play in the mixture of consent and consensus that underpins international law.

Dumberry,P., The Formation and Identification of Rules of Customary International Law in International Investment Law, Cambridge, United Kingdom, Cambridge University Press, 2016.

Rules of customary international law provide basic legal protections to foreign investors doing business abroad. These rules remain of fundamental importance today despite the growing number of investment treaties containing substantive investment protection. In this book, Patrick Dumberry provides a comprehensive analysis of the phenomenon of custom in the field of international investment law. He analyses two fundamental questions: how customary rules are created in this field and how they can be identified. The book examines the types of manifestation of State practice which should be considered as relevant evidence for the formation of customary rules, and to what extent they are different from those existing under general international law. The book also analyses the concept of States' opinio juris in investment arbitration. Offering guidance to actors called upon to apply customary rules in concrete cases, this book will be of significant importance to those involved in investment arbitration.

Given the literature in the field of jus cogens one might ask what could possibly be added to the body of literature already existing in field? Robert Kolb, one of the leading international scholars of his generation, offers a seminal survey of the question of peremptory international law. The book analyses and systemises courts’ diverging approaches, and draws a typology of techniques for judicial protection afforded to individuals affected by UNSC measures. On the basis of this analysis, the book identifies the discrepancies with the international human rights law standards and proposes solutions. The study pays special attention to the persisting problem with the targeted sanctions regime, which is that the grounds and evidence on the basis of which individuals are designated remain largely confidential. The book suggests an amendment to the present UNSC procedure, which would mitigate this problem. This important book is essential reading for all scholars of the subject.

Weatherall, T., Jus Cogens: International Law and Social Contract, Cambridge, Cambridge University Press, 2015.

One of the most complex doctrines in contemporary international law, jus cogens is the immediate product of the socialization of the international community following the Second World War. However, the doctrine resonates in a centuries-old legal tradition which constrains the dynamics of voluntarism that characterize conventional international law. To reconcile this modern iteration of individual-oriented public order norms with the traditionally State-based form of international law, Thomas Weatherall applies the idea of a social contract to structure the analysis of jus cogens into four areas: authority, sources, content and enforcement. The legal and political implications of this analysis give form to jus cogens as the product of interrelation across an individual-oriented normative framework, a State-based legal order, and values common to the international community as a whole.

Pedretti, R., Immunity of Heads of State and State Officials for International Crimes, Leiden, Boston, Brill Nijhoff, 2015.

Ramona Pedretti offers, for the first time, a comprehensive assessment of the rules of customary international law relating to immunity of Heads of State and other State officials in the context of crimes pursuant to international law and their relationship with core principles of international law. The book gives the reader a full picture of this topical issue which is located at the heart of today's development of international law. It contains an in-depth evaluation of a vast amount of relevant material, ranging from domestic laws to judicial decisions of domestic and international courts. The fact that the International Law Commission is deliberating the issue with a view to drafting an international treaty underscores the book's importance and timeliness.

Conference about ICJ's judgment in the case between Nicaragua and the USA

In 1986, the International Court of Justice issued its judgment on the merits in a dispute between Nicaragua and the United States of America. Twenty-five years later, members of the legal teams of both Nicaragua and the United States faced each other once again in the Peace Palace.